Witch

/* Sum numbers 0 ... 9 two at a time            */
/* index increments                             */
/* sum() function uses "pass by reference"      */
/* even if it's only about one "return value"   */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

void sum(int, int, int * );


int main(int argc, char *argv[])
{
    int array[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    int array_copy[10];
    int i, j;


    for(i=0; i<10; i++)
        array_copy[i]=array[i];

    for(j=0; j<10; j++)
        printf("%d\n", array_copy[j]);

    printf("\n");
    printf("__________________________________________");
    printf("\n\n");


    for( i=0; i<9; i++)
    {
        sum(array[i], array[i+1], &array[i+1]);
        printf("Partial sum %d equals: %d\n", i+1, array[i+1]);
    }

    printf("\nGrandtotal equals: %d\n", array[9]);

    printf("\n");
    printf("__________________________________________");
    printf("\n\n");

    for(j=0; j<10; j++)
        printf("%d\n", array_copy[j]);

    printf("\n\n");

    system("PAUSE");
    return 0;
}


/*************
* Functions
*************/
/* ___________________________________________________________________________*/

void sum(int a, int b, int *summa )
{
    *summa = a + b;  /* return with "pass by reference" */
}